In 1966, Haise was one of 19 new astronauts selected for NASA Astronaut Group 5. He had already been working with NASA for several years as a civilian research pilot. He was the first astronaut among his class to be assigned to a mission, serving as backup Lunar Module Pilot for both Apollo 8 and Apollo 11.[3]

Haise remained in the astronaut rotation and served as the backup mission Commander for Apollo 16. Though there was no formal selection, Haise was prospectively slated to command Apollo 19 with William R. Pogue as Command Module Pilot and Gerald P. Carr as Lunar Module Pilot. However, the mission was canceled in late 1970 due to budget cuts.[9]

Haise was originally slated to command the second Space Shuttle mission, which would have delivered a booster module that would have boosted the Skylab space station to a higher orbit, preserving it for future use. However, delays in the Shuttle program development as well as an unexpected increase in Skylab's orbital decay led to the mission being abandoned. Skylab was destroyed upon entering the Earth's atmosphere in July 1979, while the Space Shuttle did not launch until April 1981.[15]

He is married to the former F. Patt Price of Rogers, Texas. He has four grown children: Mary M. (born January 25, 1956), Frederick T. (born May 13, 1958), Stephen W. (June 30, 1961), and Thomas J. (born July 6, 1970).